Study of fast ignition target design for ignition and burning experiments

Nagatomo, Hideo; Johzaki, Tomoyuki; Asahina, Takashi; Hata, Masayuki; Sentoku, Y.; Mima, K.; Sakagami, Hiroyuki

doi:10.1088/1741-4326/ab3a5d

Cited by 13 publications

(6 citation statements)

References 25 publications

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“…In the fast ignition scheme [6][7][8][9] , a short and intense pulse of energetic charged particles-electrons, protons, or heavy ions-generated by an ultra-high-intensity laser, is directed toward the pre-compressed fusion pellet. The charged-particle beam requirements to achieve ignition have been discussed and studied in detail previously [10][11][12][13][14] based on single-particle stopping theory. However, the collective effects induced by high-current charged-particle beams could alter significantly the projected range, the magnitude of energy deposition, and therefore change the requirements for ignition correspondingly.…”

mentioning

confidence: 99%

Observation of a high degree of stopping for laser-accelerated intense proton beams in dense ionized matter

Ren

Deng

et al. 2020

Nat Commun

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Intense particle beams generated from the interaction of ultrahigh intensity lasers with sample foils provide options in radiography, high-yield neutron sources, high-energy-density-matter generation, and ion fast ignition. An accurate understanding of beam transportation behavior in dense matter is crucial for all these applications. Here we report the experimental evidence on one order of magnitude enhancement of intense laser-accelerated proton beam stopping in dense ionized matter, in comparison with the current-widely used models describing individual ion stopping in matter. Supported by particle-in-cell (PIC) simulations, we attribute the enhancement to the strong decelerating electric field approaching 1 GV/m that can be created by the beam-driven return current. This collective effect plays the dominant role in the stopping of laser-accelerated intense proton beams in dense ionized matter. This finding is essential for the optimum design of ion driven fast ignition and inertial confinement fusion.

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confidence: 99%

Observation of a high degree of stopping for laser-accelerated intense proton beams in dense ionized matter

Ren

Deng

et al. 2020

Nat Commun

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“…In our previous studies, we have proposed an optimal target design for burning-scale-size target of fast ignition [5]. However, there was still much room for improvement.…”

Section: Optimization Of Cone-inserted Implosion Of Solid Targetmentioning

confidence: 99%

“…We use a low-Z material to suppress the divergence angle of the electron beam at the tip of the gold cone. Based on the previous optimized design [5], the radius of the tip of the cone is varied from r tip = 30 μm to r tip = 18.9 μm and r tip = 13.8 μm. For the case of r tip = 13.8 μm, the configuration of the initial target is shown in figure 1.…”

Section: Optimization Of Cone-tip Radius With 2d Radiation Hydrodynam...mentioning

confidence: 99%

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Improvement of ignition and burning target design for fast ignition scheme

et al. 2021

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For the fast ignition scheme of laser fusion, a highly compressed fuel core is necessary using a cone-inserted spherical solid target. We design an optimal compression method with a multistep laser pulse shape using a 2D radiation hydrodynamics simulation. In the design, the maximum areal density is ρR max = 0.46 g cm−2 with 8 kJ of implosion laser. Considering the scaling law of hydrodynamic, we obtained 82 kJ and 1.3 MJ for the ignition-scale-target (ρR max = 1.1 g cm−2) and burning-scale-target (ρR max = 2.5 g cm−2), respectively. In a preliminary study of hydrodynamic instability in the optimized cone-inserted implosion, there is no significant growth of the instabilities that affect the implosion performance. A parameter search to investigate the feasibility and robustness of a high areal density design for changes in the laser pulse shape is performed. As a result, a delay of several tens of pico-second of the rising laser pulse is acceptable.

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“…In the fast ignition scheme [25,26], a short and intense pulse of energetic charged particles -electrons, protons or heavy ions -generated by an ultrahigh intensity laser, is directed towards the pre-compressed fusion pellet. The chargedparticle beam requirements to achieve ignition have been discussed and studied in detail previously [27][28][29][30][31] based on single-particle stopping theory. However, the collective effects induced by high-current charged particle beams could alter significantly the projected range, the magnitude of energy deposition, and therefore change the requirements for ignition correspondingly.…”

mentioning

confidence: 99%

Anomalous stopping of laser-accelerated intense proton beam in dense ionized matter

Ren,

Deng,

et al. 2020

Preprint

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Ultrahigh-intensity lasers (10 18 -10 22 W/cm 2 ) have opened up new perspectives in many fields of research and application [1][2][3][4][5]. By irradiating a thin foil, an ultrahigh accelerating field (10 12 V/m) can be formed and multi-MeV ions with unprecedentedly high intensity (10 10 A/cm 2 ) in short time scale (∼ps) are produced [6][7][8][9][10][11][12][13][14]. Such beams provide new options in radiography [15], high-yield neutron sources [16], high-energy-density-matter generation [17], and ion fast ignition [18,19]. An accurate understanding of the nonlinear behavior of beam transport in matter is crucial for all these applications. We report here the first experimental evidence of anomalous stopping of a laser-generated high-current proton beam in well-characterized dense ionized matter. The observed stopping power is one order of magnitude higher than single-particle slowing-down theory predictions. We attribute this phenomenon to collective effects where the intense beam drives an decelerating electric field approaching 1GV/m in the dense ionized matter. This finding will have considerable impact on the future path to inertial fusion energy.

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Study of fast ignition target design for ignition and burning experiments

Cited by 13 publications

References 25 publications

Observation of a high degree of stopping for laser-accelerated intense proton beams in dense ionized matter

Observation of a high degree of stopping for laser-accelerated intense proton beams in dense ionized matter

Improvement of ignition and burning target design for fast ignition scheme

Anomalous stopping of laser-accelerated intense proton beam in dense ionized matter

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